Introduction to Electromobility

Frontmatter

Chapter 1. Introduction

Abstract

The fundamentals of electric drives are already around 200 years old, and the first electric vehicles were built over 120 years ago. This chapter provides an overview of the development of the technologies required for a modern electric car, from the electric motor to the power electronics and the battery.

Martin Doppelbauer

Chapter 2. Drives for Electric Vehicles

Abstract

This chapter presents the main operating characteristics of electric traction drives, in particular the speed/torque characteristics and the operating point-dependent losses. Similarities and differences to conventional internal combustion engines are shown. Emphasis is placed on the explanation of the constant torque and constant power range as well as the various operating limits in continuous and short-time operations.

Martin Doppelbauer

Chapter 3. Hybrid Vehicle Drives

Abstract

This chapter introduces the hybrid vehicle types, operating modes, and technologies. An overview is given of the common motor and transmission variants for hybrid and fully electric passenger cars. The hybrid vehicle classes from micro-hybrid to plug-in hybrid are presented in detail. The required motor power and battery capacities and the technical functionalities are presented. The shell diagram of the combustion engine is used to illustrate how fuel savings can be realized through hybrid drives and their potential. Finally, the hybrid powertrains (serial, parallel, and power-split hybrid drive) are discussed. The planetary gearbox, which is presented in detail in a separate section, is essential for power-split drives.

Martin Doppelbauer

Chapter 4. Driving Resistances and Energy Consumption

Abstract

The driving resistance force is made up of various components. Together with the speed, this results in the required drive power. In electric cars, part of the energy used during braking can be recovered by braking energy recovery. The chapter introduces the most common driving cycles worldwide and describes how the energy consumption of hybrid vehicles is measured. Finally, the CO₂ efficiency classes of passenger cars are presented.

Martin Doppelbauer

Chapter 5. Operating Strategy

Abstract

The selection of the best operating strategy by the hybrid controller depending on the situation is essential for the success in minimizing the consumption of an electric or hybrid vehicle. Many concepts and algorithms are known for this purpose, some of which are presented in this section.

Martin Doppelbauer

Chapter 6. Energy Storage Systems

Abstract

This chapter covers the basics of electrochemical energy storage systems. The most important variants—lead-acid batteries, nickel–metal hydride batteries, and lithium-ion batteries—are presented in detail. The lithium-ion battery in particular has a variety of different materials for the anode, cathode, and electrolyte, resulting in some very different operating characteristics. Separate sections are devoted to the various charging methods, charge balancing between the various parallel-connected cells, cell designs, and the structure of battery storage systems (stack, battery management). Modeling the operating behavior of lithium-ion batteries as accurately as possible is necessary to control fast charging in such a way that no irreversible damage occurs. Suitable models are presented. In the final sections of the chapter, the hydrogen storage is discussed.

Martin Doppelbauer

Chapter 7. Fundamentals of Electric Machines

Abstract

After a brief introduction to the basic functional principle of electric machines and the three-phase system, the three main basic variants of electric machines, the induction machine, the externally excited, and the permanent magnet synchronous machine, are presented. This is followed by an overview of the designs of the stator and rotor of these three motor variants. The physical background of braking energy recovery (voltage generation) and motor operation (magnetic forces) is explained in more detail. The base speed range and the field weakening range, which were presented purely phenomenologically in the second chapter, are now introduced in detail on the basis of the magnetic properties of the motor. The chapter concludes with an overview of the properties of the materials used and the losses that occur in electric machines.

Martin Doppelbauer

Chapter 8. Synchronous Machines

Abstract

This chapter is dedicated to the detailed description of the function and operating characteristics of synchronous machines in their various forms. In particular, the description of the machine behavior and the control in d–q coordinates are explained. This results in the equations for describing the generation of torque from synchronous torque and reluctance torque. The parameter plane is introduced in a short section. It enables a systematic rotor design to achieve the desired torque–speed behavior. Finally, critical operating states such as short circuit and sudden loss of load are discussed, which must be mastered in the event of a fault.

Martin Doppelbauer

Chapter 9. Induction Machines (IM)

Abstract

In the short chapter on asynchronous machines, the equations for the single-phase equivalent circuit diagram are explained. The torque and operating behavior can be derived from this.

Martin Doppelbauer

Chapter 10. Power Electronic Components

Abstract

This chapter presents the most important semiconductors and power electronic components that make up the assemblies required in hybrid and electric vehicles, in particular, DC/DC and DC/AC converters. These are primarily semiconductor valves (diodes) and power electronic switches (MOSFET, IGBT).

Martin Doppelbauer

Chapter 11. Topology of Electric Drivetrains

Abstract

In this chapter, the basic structure and function of the main components of the electric drivetrain, namely, power electronic components are presented in a brief overview. The connection between the battery (DC) and the motor (AC) is established via power electronic energy converters. A distinction is made between DC/AC and DC/DC converters. This chapter presents the various switching and control concepts. Further sections are devoted to the control of current, voltage, torque, and speed of the two types of electrical machine (synchronous and induction motor).

Martin Doppelbauer

Chapter 12. Charging Systems

Abstract

The chapter provides an overview of charging methods for EVs. This is followed by a detailed discussion of the different plug variants and their performance. The focus is on conductive charging for cars, but systems for commercial vehicles and contactless systems are also briefly discussed. The chapter ends with an overview of the technical characteristics of hydrogen refueling stations.

Martin Doppelbauer

Chapter 13. Framework of Individual Mobility

Abstract

Based on the concept of sustainability, this chapter motivates and explains regional and global climate protection efforts and targets. This is followed by an overview of the global automotive landscape: vehicle fleets, consumption, and mileage. Further sections shed light on global emissions in connection with electricity production, the switch to renewable energies, and the status of electromobility. The chapter concludes with a discussion of the various raw materials required for electromobility. Their range, production conditions, and possible environmental damage. And finally, a section on second use and recycling of batteries.

Martin Doppelbauer

Chapter 14. Production and Distribution of Energy

Abstract

This chapter highlights various technical options for supplying mobile vehicles with energy. The energy chains from the provision of primary energy to the energy carriers at the filling or charging stations are presented. First, the most important primary energy sources and energy carriers are presented with their chemical properties. In the case of finite primary energies, the currently available reserves and the achievable ranges are presented. For renewable raw materials, the land requirements are estimated accordingly. An extensive section is devoted to electricity production from conventional and renewable energy sources, including the necessary distribution grids and their stability. The chapter concludes with a section on hydrogen. The various options for producing hydrogen and distributing it at filling stations are briefly presented. A further section highlights the many ways in which hydrogen can be used in vehicles, for grid stabilization and in industrial processes.

Martin Doppelbauer

Chapter 15. Life-Cycle Assessment

Abstract

This chapter discusses the direct and indirect harmful emissions from cars and how these can be assessed and compared. Building on the findings of the previous chapters, examples are then given of how emissions from the operation of cars with different drive technologies can be calculated. However, such considerations are not sufficient for a comprehensive assessment of the footprint of a car technology. Rather, the costs of production, the entire use phase, and possible recycling must also be considered. Such life-cycle analyses are introduced and presented using average cars as examples.

Martin Doppelbauer

Chapter 16. Costs of Electric Mobility

Abstract

This chapter estimates the costs of electric vehicles, batteries, and the necessary infrastructure. The studies on infrastructure are carried out using Germany as an example, whereby the year 2050 is assumed as the limit scenario, when hopefully all cars will be emission-free battery electric vehicles. The distribution of charging points is estimated on this basis. The estimated costs per charging point then result in an investment sum for the expansion of the infrastructure.

Martin Doppelbauer

Backmatter